The Partition of Bengal made by Lord Curzon in 1905 lasted until

the First World War when Indian troops were needed by the British and the partition was ended
King George V abrogated Curzon's Act at the Royal Durbar in Delhi in 1911
Gandhiji launched his Civil Disobedience Movement
the Partition of India in 1947 when East Bengal became East Pakistan

Answer

King George V abrogated Curzon's Act at the Royal Durbar in Delhi in 1911

(a) Incorrect. The 1905 Partition of Bengal was annulled in 1911, not during the First World War; WWI began in 1914.
(b) Correct. King George V announced the annulment at the Delhi Durbar in 1911; Bengal was reunited and Bihar-Orissa were separated.
(c) Incorrect. Gandhiji’s Civil Disobedience Movement began in 1930, long after the partition had already been ended.
(d) Incorrect. The 1905 partition did not last till 1947; although Bengal was partitioned again in 1947, Curzon’s partition had been revoked in 1911.